Power Ancillary Service Option - LP Turbine Outage Scheme, its Peaking Load Performance and Cost

As one of the modification options to enhance the peaking load regulating capability of existing cogeneration units, LP turbine outage upgrading scheme has been adopted increasingly in the past few years, yet many of the studies focused on the operation safety of the LP turbine outage scheme, its’ influence on increasing of the heating capacity and unit economic performance indexes. Here the full influence of this upgrading scheme on peak load regulating capability and economic benefit of the unit are addressed. The performance of one typical 300MW cogeneration unit adopting the specified scheme is studied based on the model simulation of the EBSILON software. The results indicate that minimum peaking load of the modified unit decreases with the decreasing of the heating load, and the peaking power loss under upgrading operation mode is basically unchanged when the heating load changes, which is maintained at about 51MW. Significant unit operational economic benefit loss is paralleled with the peaking power loss, and the calculated compensation standard or cost for peaking power loss is within the range of 0.14~0.15 Yuan/kWh. This study provides an overview picture of the specified upgrading scheme, including the peak load regulating capability improvement and the relevant operational economic benefit loss incurred, which is very critical for the decision making of the scheme. The calculated compensation standard or cost for peaking power loss can be regarded as a baseline for plant owners to make competitive bidding in the power ancillary service markets.